Binary releases are no longer available on mozilla. JSS is a JNI library we provide the jss4.jar but expect you to build the JSS's matching JNI shared library. We provide the jss4.jar in case you do not want to obtain your own JCE code signing certificate. JSS is a JCE provider and therefore the jss4.jar must be signed. https://archive.mozilla.org/pub/security/jss/releases/JSS_4_3_RTM/